National Instruments PC-DIO-96 用户手册

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4-1

Introduction ...................................................................................................................

 

4-1

Register Map .................................................................................................................

 

4-2

Register Descriptions ....................................................................................................

 

4-3

Register Description for the 82C55A ................................................................

 

4-3

Register Description for the 8253 .....................................................................

 

4-4

Register Description for the Interrupt Control Registers ..................................

 

4-5

Interrupt Control Register 1 ..................................................................

 

4-6

Interrupt Control Register 2 ..................................................................

 

4-8

Programming Considerations for the 82C55A ..............................................................

 

4-9

Modes of Operation for the 82C55A .................................................................

 

4-9

Mode 0 ...................................................................................................

 

4-9

Mode 1 ...................................................................................................

 

4-9

Mode 2 ...................................................................................................

 

4-10

Single Bit Set/Reset Feature ..................................................................

 

4-10

Mode 0—Basic I/O ...........................................................................................

 

4-10

Mode 0 Programming Example ............................................................

 

4-11

Mode 1—Strobed Input .....................................................................................

 

4-12

Mode 1 Input Programming Example ...................................................

 

4-14

Mode 1—Strobed Output ..................................................................................

 

4-15

Mode 1 Output Programming Example ................................................

 

4-16

Mode 2—Bidirectional Bus...............................................................................

 

4-17

Mode 2 Programming Example ............................................................

 

4-19

Interrupt Programming Examples for the 82C55A ...........................................

 

4-19

Programming Considerations for the 8253 ...................................................................

 

4-21

General Information ..........................................................................................

 

4-21

Interrupt Programming Example for the 8253 ..................................................

 

4-22

Interrupt Handling .........................................................................................................

 

4-28

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A-1

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B-1

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C-1

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D-1

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Glossary-1

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Index-1